JP7052249B2 - Image forming device, device for discharging liquid - Google Patents

Description

The present invention relates to an image forming apparatus and a device for discharging a liquid.

An image forming apparatus is known that forms an image using so-called UV (Ultraviolet) ink that is cured by irradiating with ultraviolet rays.

For example, an image forming apparatus including an inkjet head that ejects UV ink and a UV lamp that cures the UV ink can be mentioned. This image forming apparatus includes a transport device including a platen drum for transporting a web-shaped recording medium by winding it around an outer peripheral surface (see, for example, Patent Document 1).

On the other hand, an image forming apparatus using a water-based ink is known. Since the water-based ink is difficult to dry, an image forming apparatus using the water-based ink requires a drying portion for drying the water-based ink. Further, in order not to disturb the image, it is necessary to transport the web-shaped recording medium to the drying portion so that the image-forming surface of the web-shaped recording medium on which the image is formed by the water-based ink does not come into contact with any member.

A platen drum for transporting the web-shaped recording medium by winding it around the outer peripheral surface is provided, and in order to transport the image to the drying portion so that the surface on which the image is formed by the water-based ink does not come into contact with any member, the lower part of the platen drum is provided. It is necessary to arrange a drying part or pull out the web-shaped recording medium on which the image has been formed on the side of the introduction port of the web-like recording medium to the platen drum, introduce it into the drying part, and then invert it and discharge it. In either case, there is a problem that the transport device including the platen drum and the drying portion becomes tall.

If the transport device becomes taller, it may not be possible to load it into the transport container in the completed state. In this case, the transport device must be disassembled and transported, and it will be assembled locally, which prolongs the installation period and increases costs. Problems such as inviting occur.

The present invention has been made in view of the above, and an object of the present invention is to prevent the height of a transport device for transporting a web-shaped recording medium in an image forming device and a device for discharging a liquid .

The image forming apparatus includes a rotating body that winds the web-shaped recording medium around a predetermined area on the outer peripheral surface with one surface of the web-shaped recording medium facing outward, and conveys the web-shaped recording medium as it rotates. The drying section, which is arranged downstream of the rotating body in the transport direction of the web-shaped recording medium to dry the web-shaped recording medium and transport the web-shaped recording medium, and the drying section between the rotating body and the drying section. It has a transport direction changing portion which is arranged on the transport path of the web-shaped recording medium and changes the transport direction of the web-shaped recording medium, and the outer peripheral surface of the transport direction changing portion is the said of the web-shaped recording medium. A facing region facing one surface is provided, and the facing region is provided with an opening for ejecting gas toward the one surface of the web-shaped recording medium, and the rotating body and the drying portion are flat. The dried portion does not overlap visually, and the dried portion is arranged on the side closer to the discharge port of the web-shaped recording medium than the rotating body in a plan view. A pressure detecting unit that has a second rotating body that is wound around a region and conveys the web-shaped recording medium as it rotates, and that detects the internal pressure of the conveying direction changing unit, and the rotation speed of the second rotating body. It has a rotation control unit to control, and the rotation control unit detects the tension of the web-shaped recording medium based on the internal pressure detected by the pressure detection unit, and compares the tension with a preset numerical value. An image forming the transfer device that controls the rotation speed of the second rotating body based on the comparison result and an image formed on one surface of the web-shaped recording medium arranged opposite to the outer peripheral surface of the rotating body. It is a requirement to have a department .

According to the disclosed technique, in the image forming apparatus and the apparatus for discharging the liquid, it is possible to prevent the conveying device for conveying the web-shaped recording medium from becoming taller.

It is a figure which shows typically an example of the image forming apparatus which concerns on 1st Embodiment. It is a figure which illustrates the hardware composition of the control part. It is a figure which illustrates the functional block of a control part. It is a figure which illustrates the relationship between the winding angle θ and the transport force F. It is a schematic diagram explaining the structural example of the air turnstile system which concerns on 1st Embodiment. This is an example of a flowchart for controlling the supply amount of gas supplied by the blower. This is an example of a flowchart for controlling the tension of a web-like recording medium. It is a figure which shows an example of the image forming apparatus which concerns on the comparative example 1. schematically. It is a figure which shows an example of the image forming apparatus which concerns on the comparative example 2 schematically. It is a schematic diagram explaining the structural example of the air turnstile system which concerns on the modification of 1st Embodiment. It is another example of the flowchart which controls the supply amount of the gas supplied by a blower. This is an example of a flowchart for controlling the supply amount of gas supplied by the blower and the tension of the web-shaped recording medium.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate explanations may be omitted.

<First Embodiment>
FIG. 1 is a diagram schematically showing an example of an image forming apparatus according to the first embodiment. As shown in FIG. 1, the image forming apparatus 1 has, as main components, a paper feed transport unit 10, a platen drum 20, an image forming unit 30, an air turnir system 40, a drying unit 50, and paper ejection. It has a transport unit 60 and a control unit 70. A portion including the platen drum 20, the air turnbar system 40, and the drying portion 50 may be referred to as a transport device. The transport device may further include a paper feed transport unit 10 (first transport unit) and a paper discharge transport unit 60 (second transport unit).

FIG. 2 is a diagram illustrating a hardware configuration of the control unit. As shown in FIG. 2, the control unit 70 has a CPU 71, a ROM 72, a RAM 73, an I / F 74, and a bus line 75 as main components. The CPU 71, ROM 72, RAM 73, and I / F 74 are connected to each other via a bus line 75. The control unit 70 is connected to various control targets, various sensors, and the like.

The CPU 71 controls each function of the control unit 70. The ROM 72, which is a storage means, stores a program executed by the CPU 71 to control each function of the control unit 70 and various information. The RAM 73, which is a storage means, is used as a work area or the like of the CPU 71. Further, the RAM 73 can temporarily store predetermined information. The I / F 74 is an interface for connecting to another device or the like, and is connected to, for example, an external network or the like.

However, a part or all of the control unit 70 may be configured by hardware. Examples of hardware include ASIC (Application Specific Integrated Circuit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), and the like.

FIG. 3 is a diagram illustrating a functional block of the control unit. As shown in FIG. 3, the control unit 70 has a rotation control unit 710, a discharge control unit 720, a drying control unit 730, and a gas supply amount control unit 740 as main functional blocks. The specific functions of each functional block will be described later in the description of each figure. The control unit 70 may have other functional blocks as needed.

Returning to FIG. 1, the image forming apparatus 1 includes an introduction port 101 and an discharge port 102. The image forming apparatus 1 introduces the web-shaped recording medium 300 unwound from the unwinding device arranged outside the image forming apparatus 1 from the introduction port 101 in the direction of arrow A, and introduces the surface of the web-like recording medium 300 (one side). After forming an image on the surface of), the image is discharged from the discharge port 102 in the direction of arrow B. The web-like recording medium 300 is, for example, continuous paper, but the material of the web-like recording medium 300 is not limited to paper.

The web-shaped recording medium 300 discharged in the direction of the arrow B is delivered to a subsequent processing device arranged outside the image forming device 1. The processing device in the subsequent stage is, for example, a turn bar that flips the front and back in order to form an image on the back surface (the other surface) of the web-shaped recording medium 300 on which the image is formed on the front surface, and the web-like recording medium 300 on which the image is formed. It is a winding device for winding a roll, a post-processing device such as a cutter and a laminator, and the like.

The web-shaped recording medium 300 introduced in the direction of arrow A from the introduction port 101 includes, for example, a plurality of transfer idler rollers 11, a transfer drive roller pair 12, an EPC (Edge Position Control) device 13, and a tension roller 14. It passes through the transport unit 10 and is wound around the platen drum 20 and transported.

The transport drive roller pair 12 includes, for example, a drive roller 12a and a pinch roller 12b. The rotation control unit 710 of the control unit 70 controls the drive source that drives the drive roller 12a, and rotates the drive roller 12a at a predetermined rotation speed. As a result, the web-like recording medium 300 is conveyed. The EPC device 13 is a device that adjusts the position of the web-shaped recording medium 300 in the width direction to a specified position. The tension roller 14 is provided with a pressure detecting mechanism such as a load cell in the bearing portion, and detects the tension of the web-shaped recording medium 300.

The platen drum 20 is a rotating body that winds the web-shaped recording medium 300 around a predetermined area on the outer peripheral surface with the surface on which the image of the web-shaped recording medium 300 is formed facing outward, and conveys the web-shaped recording medium as it rotates. be. Specifically, the rotation control unit 710 of the control unit 70 controls the drive source for driving the platen drum 20, and rotates the platen drum 20 at a predetermined rotation speed. The tension of the web-shaped recording medium 300 generated by the rotation of the platen drum 20 is detected by the tension roller 14 and input to the control unit 70. The rotation control unit 710 of the control unit 70 controls the rotation speed of the transport drive roller pair 12 so that the tension detected by the tension roller 14 becomes a preset value. As a result, the web-shaped recording medium 300 is conveyed while maintaining a predetermined tension.

At the upper part of the platen drum 20 in the vertical direction, an image forming unit 30 is arranged so as to face the outer peripheral surface of the platen drum 20 and form an image on the web-shaped recording medium 300. The image forming unit 30 can form an image with, for example, water-based ink. The water-based ink is an ink that uses water as a solvent, and is, for example, a water-based dye ink or a water-based pigment ink.

The image forming unit 30 includes, for example, a plurality of inkjet recording head arrays (IJ head arrays) arranged along the outer periphery of the platen drum 20 in the transport direction of the web-shaped recording medium 300. Each IJ head array includes, for example, a plurality of IJ heads juxtaposed in a direction orthogonal to the transport direction of the web-shaped recording medium 300.

In FIG. 1, as an example, the image forming unit 30 ejects an IJ head array 31 that ejects K ink (black ink), an IJ head array 32 that ejects C ink (cyan ink), and M ink (magenda ink). It is composed of an IJ head array 33, an IJ head array 34 that ejects Y ink (yellow ink), and an IJ head array 35 that ejects spot color ink.

The image forming unit 30 is controlled by the control unit 70. The ejection control unit 720 of the control unit 70 allocates nozzles to be ejected to each IJ head constituting the IJ head arrays 31 to 35 based on the print data 500 received from the outside of the image forming apparatus 1 and controls the ejection timing. do.

The platen drum 20 includes a detection device 25 that detects the amount of movement of the drum surface (outer peripheral surface), and the detection signal of the detection device 25 is input to the control unit 70. The discharge control unit 720 of the control unit 70 detects the correlation between the discharge timing of each IJ head constituting the IJ head arrays 31 to 35 and the movement amount of the platen drum 20 based on the detection signal of the detection device 25, and the web The ejection timing can be corrected according to the transport amount of the state recording medium 300.

FIG. 4 is a diagram illustrating the relationship between the winding angle θ and the transport force F, and shows the winding angle θ and the transport force F when the web-shaped recording medium 300 is wound around the platen drum 20 with a tension T1 and transported. Shows the relationship. T1 is the tension on the tension roller 14 side, and T2 is the tension on the air turntile system 40 side.

Here, assuming that the width of the web-shaped recording medium 300 is W and the static friction coefficient between the web-shaped recording medium 300 and the platen drum 20 is μ, the relationship between T1 and T2 and the carrying force F are given by the equations (1) and (2). Can be represented by.

制御部７０の吐出制御部７２０が吐出タイミングを補正した結果を忠実に印刷に反映するためには、ウェブ状記録媒体３００をプラテンドラム２０と固着又はマイクロスリップ状態を維持しながら搬送することが必要になる。そのため、搬送力Ｆを張力Ｔ１に対して十分に大きくしておくことが望ましい。

In order for the ejection control unit 720 of the control unit 70 to faithfully reflect the result of correcting the ejection timing in printing, it is necessary to convey the web-shaped recording medium 300 while maintaining the platen drum 20 and the platen drum 20 in a fixed or microslip state. become. Therefore, it is desirable that the transport force F be sufficiently large with respect to the tension T1.

The graph in FIG. 4 shows the relationship between the winding angle θ and the safety factor with respect to the tension of the transport force F. The static friction coefficient μ is empirically about 0.3, but the variation is taken into consideration. Μ = 0.2. The graph of FIG. 4 shows that the safety factor is doubled or more when the winding angle θ is 200 degrees or more. That is, it is shown that if the web-shaped recording medium 300 is wound around the platen drum 20 by 200 degrees or more, a transport force F that can withstand an external force of twice or more the tension without slipping can be obtained.

Therefore, by designing the winding angle θ of the web-shaped recording medium 300 on the platen drum 20 to be 200 degrees or more, it is possible to carry the web-shaped recording medium 300 with sufficient margin against slip. ..

Further, in the above configuration, since the web-shaped recording medium 300 is tightly wound around the outer peripheral surface of the platen drum 20 and conveyed, the web-shaped recording medium 300 does not flutter. As a result, since the IJ head arrays 31 to 35 constituting the image forming unit 30 do not come into contact with the web-shaped recording medium 300, the IJ head arrays 31 to 35 are moved to the extent that contact due to the runout of the platen drum 20 can be avoided. It can be placed close to the platen drum 20.

Since each of the IJ heads constituting the IJ head arrays 31 to 35 has a variation in the ejection angle for each nozzle, the variation in the landing position of the ink droplet is small by reducing the distance between each IJ head and the platen drum 20. Therefore, higher image quality printing becomes possible.

Returning to FIG. 1, the web-shaped recording medium 300 passing through the platen drum 20 is conveyed substantially downward from the platen drum 20. Then, the web-shaped recording medium 300 winds around the outer peripheral surface of the air turn bar 41 constituting the air turn bar system 40 (for example, the outer peripheral surface having an arcuate region in a side view), and the transport direction is changed substantially upward. Will be done. Then, the web-shaped recording medium 300 whose transport direction is changed to be substantially upward is transported to the drying unit 50 through the transport idler roller 49. Details of the air turnbar system 40 will be described later.

The drying section 50 is arranged downstream of the platen drum 20 and the air turnbar 41 in the transport direction of the web-shaped recording medium 300, and the image forming section 30 dries the image formed on the web-shaped recording medium 300 and the web-shaped recording medium 300. To transport. The drying unit 50 dries the undried water-based ink, for example, in the image formed by the image forming unit 30. The drying portion 50 is arranged at a position that does not overlap with the platen drum 20 in a plan view, and has a tension roller 51, a drying drum 52, a heater 53, and a plurality of air nozzles 54.

In addition, the plan view means that the image forming apparatus 1 is arranged on a horizontal plane in a state where it can be normally used, and is viewed from the normal direction of the horizontal plane.

The tension roller 51 is provided with a pressure detecting mechanism such as a load cell in the bearing portion as a tension detecting means, and detects the tension of the web-shaped recording medium 300 applied between the platen drum 20 and the drying drum 52. The tension roller 51 is a typical example of the tension detection unit according to the present invention.

The drying drum 52 winds the web-shaped recording medium 300 around a predetermined area on the outer peripheral surface with the surface on which the image of the web-shaped recording medium 300 is formed facing outward, and conveys the web-shaped recording medium as it rotates. The drying drum 52 is a typical example of the second rotating body according to the present invention.

The rotation control unit 710 of the control unit 70 controls the rotation speed of the drying drum 52. Specifically, the rotation control unit 710 controls the drive source for driving the drying drum 52, and rotates the drying drum 52 at a predetermined rotation speed. The tension of the web-shaped recording medium 300 generated by the rotation of the drying drum 52 is detected by the tension roller 51 and input to the control unit 70. The rotation control unit 710 of the control unit 70 controls the rotation speed of the drying drum 52 so that the tension detected by the tension roller 51 becomes a preset value. As a result, the web-shaped recording medium 300 can be conveyed while maintaining the tension of the web-shaped recording medium 300 between the platen drum 20 and the drying portion 50 at a predetermined value.

The tension detecting means included in the tension roller 51 is not limited to the load cell. For example, the tension roller 51 may be swingably supported, pressed by an elastic member in the tension direction of the web-shaped recording medium 300, and the tension of the web-shaped recording medium 300 may be detected by pressing and measuring the tension roller 51. ..

Inside the drying drum 52, a heater 53 composed of, for example, a halogen lamp or the like is arranged. Further, an air nozzle 54 is arranged so as to surround the periphery of the drying drum 52. The heating amount of the heater 53 and the spraying amount of the air nozzle 54 are controlled by the drying control unit 730 of the control unit 70. The web-shaped recording medium 300 wound around the drying drum 52 is heated from the back surface side (back surface side) of the image forming surface by the heater 53, and air (normal temperature) is placed on the image forming surface side (front surface side) by the air nozzle 54. Or blow warm air directly. As a result, the ink ejected to the web-shaped recording medium 300 can be dried.

In addition, depending on the physical characteristics of the ink and the productivity required for the apparatus, the drying unit 50 may be equipped with a technique for drying by heat radiation such as an infrared heater to promote the drying.

The ink dried by the drying portion 50 is formed into a film so as to be in contact with the surface thereof. After drying, the web-shaped recording medium 300 passes through, for example, a paper discharge transport unit 60 including a plurality of transport idler rollers 61, a tension roller 62, and a transport drive roller pair 63, and is discharged from the discharge port 102 in the arrow B direction. It is handed over to the post-processing equipment in the latter stage.

The transport drive roller pair 63 includes, for example, a drive roller 63a and a pinch roller 63b. The rotation control unit 710 of the control unit 70 controls the drive source that drives the drive roller 63a, and rotates the drive roller 63a at a predetermined rotation speed. The tension of the web-shaped recording medium 300 generated by the rotation of the drive roller 63a is detected by the tension roller 62 and input to the control unit 70. The rotation control unit 710 of the control unit 70 controls the rotation speed of the drive roller 63a so that the tension detected by the tension roller 62 becomes a preset value. As a result, the web-shaped recording medium 300 is conveyed while maintaining a predetermined tension.

Here, the air turn bar system 40 will be described in detail. 5A and 5B are schematic views illustrating a configuration example of the air turnstile system according to the first embodiment, FIG. 5A is a diagram illustrating an overall configuration, and FIG. 5B is an up and down view of the air turnstile 41. It is an inverted and enlarged figure.

As shown in FIG. 5, the air turn bar system 40 includes an air turn bar 41, a blower 42, a filter 43, a gas flow path 44, and a pressure sensor 45.

The air turnstile 41 is arranged on the transport path of the web-shaped recording medium 300 between the platen drum 20 and the drying portion 50, and the transport direction of the web-shaped recording medium 300 can be changed by, for example, 180 degrees. The air turn bar 41 is a typical example of the transport direction changing unit according to the present invention.

The blower 42 is connected to the air turnstile 41 via the gas flow path 44, and can supply gas to the air turnstile 41. The amount of gas supplied by the blower 42 is controlled by the gas supply amount control unit 740 of the control unit 70. The blower 42 is a typical example of the gas supply unit according to the present invention.

The filter 43 is inserted into the gas flow path 44 between the air turn bar 41 and the blower 42, and can remove foreign substances and the like contained in the gas supplied from the blower 42. The gas flow path 44 is a gas flow path supplied from the blower 42. Here, the gas is, for example, air.

The pressure sensor 45 is arranged in the vicinity of the air turn bar 41 and can detect the internal pressure of the air turn bar 41. The detected value of the internal pressure detected by the pressure sensor 45 is input to the control unit 70. As the pressure sensor 45, for example, a sensor having a piezo resistance can be used. The pressure sensor 45 is a typical example of the pressure detection unit according to the present invention.

In the air turnstile 41, the outer peripheral surface 411 around which the web-shaped recording medium 300 is wound has a facing region facing the surface on which the image of the web-shaped recording medium is formed. The facing region may be a part or the whole of the outer peripheral surface 411. In the facing region, a plurality of air ejection holes 412, which are openings for ejecting gas toward the surface on which the image of the web-shaped recording medium 300 is formed, are provided. The shape and arrangement pattern of the air ejection holes 412 are not particularly limited, and can be appropriately determined as needed.

The gas supplied from the blower 42 is introduced into the air turnstile 41 via the filter 43 and blown out from the plurality of air ejection holes 412 on the outer peripheral surface 411. The blown gas flows between the image forming surface of the web-shaped recording medium 300 wound along the outer peripheral surface 411 of the air turn bar 41 and the outer peripheral surface 411 of the air turntile 41, and the web-shaped recording medium 300 is transferred to the air turn bar 41. It is levitated from the outer peripheral surface 411.

In the air turnstile system 40, in order to reliably levitate and convey the web-like recording medium 300, it is necessary to supply the air turnbar 41 with a gas having a pressure sufficient to levitate the web-like recording medium 300.

In the present embodiment, a pressure sensor 45 for measuring the internal pressure of the air turn bar 41 is arranged in the vicinity of the air turn bar 41. Then, the gas supply amount control unit 740 of the control unit 70 compares the detection result of the internal pressure of the air turn bar 41 by the pressure sensor 45 with the preset numerical value, and supplies the gas supplied by the blower 42 based on the comparison result. The amount can be controlled.

Specifically, as shown in step S100 of FIG. 6, the gas supply amount control unit 740 obtains the detection result of the internal pressure of the air turn bar 41 by the pressure sensor 45 (detection value (a) of the pressure sensor 45). ..

Next, in step S101, the gas supply amount control unit 740 compares the detected value (a) of the pressure sensor 45 with the preset numerical value (pressure set value (b)), and “detects the pressure sensor 45”. (A) It is determined whether or not it is <pressure set value (b) ”. The pressure set value (b) is stored in the RAM 73, for example, and can be read out when the gas supply amount control unit 740 is required.

If it is determined in step S101 that "the detection value (a) <pressure set value (b) of the pressure sensor 45" (YES), the process proceeds to step S102, and the gas supply amount control unit 740 moves to the blower 42. Increases the supply of gas supplied by Δp.

If it is determined in step S101 that "detection value (a) of pressure sensor 45 ≥ pressure set value (b)" (NO), the process proceeds to step S103, and the gas supply amount control unit 740 moves to the blower 42. Reduces the supply of gas supplied by Δp. The process from step S100 to step S103 is repeatedly executed, but the gas supply amount control unit 740 can suspend or stop the process at a necessary timing.

By performing the control shown in FIG. 6, it becomes possible to stably supply the gas having a pressure sufficient to levitate the web-like recording medium 300 to the air turntile 41, and the web-like recording medium 300 can be reliably levitated. Can be transported.

However, this is an example of a method for stabilizing the internal pressure of the air turnstile 41, and the internal pressure of the air turnstile 41 may be stabilized by another method. For example, a plurality of pressure checkpoints are provided in the air turnstile 41, and the gas supply amount control unit 740 measures the internal pressure of the air turnstile 41 at each pressure checkpoint. Then, there is a method in which the gas supply amount control unit 740 controls the supply amount of the gas supplied by the blower 42 so that the measured value of each pressure checkpoint becomes a predetermined pressure set value.

The image forming apparatus 1 is provided with the air turnstile system 40, so that the web-shaped recording medium 300 conveyed from the platen drum 20 is conveyed in a state where the outer peripheral surface 411 of the air turn bar 41 is floated. Therefore, the image formed by the undried ink on the image forming surface of the web-shaped recording medium 300 is introduced into the drying portion 50 without being disturbed. The undried ink on the image forming surface of the web-shaped recording medium 300 is dried by the drying portion 50 and formed into a film so as to be in contact with the surface thereof.

Note that FIG. 1 shows a configuration in which the tension of the web-shaped recording medium 300 between the platen drum 20 and the drying portion 50 is detected by a detection mechanism arranged on the tension roller 51 and the tension is controlled. However, in the configuration of FIG. 5, the internal pressure of the air turn bar 41 can be detected. Therefore, instead of controlling the tension of the web-shaped recording medium 300 based on the tension detection result of the tension roller 51 as shown in FIG. 1, the following may be performed.

That is, the rotation control unit 710 of the control unit 70 applies the tension of the web-shaped recording medium 300 applied between the platen drum 20 and the drying drum 52 based on the detection result of the internal pressure of the air turn bar 41 by the pressure sensor 45. The rotation speed of the drying drum 52 may be controlled based on the detected tension. For example, the rotation control unit 710 is placed between the platen drum 20 and the drying drum 52 based on the correlation between the internal pressure of the air turn bar 41 and the tension of the web-shaped recording medium 300 wound around the outer peripheral surface 411 of the air turn bar 41. The tension of the web-shaped recording medium 300 to be applied may be detected, and the rotation speed of the drying drum 52 may be controlled based on the detected tension.

Specifically, as shown in step S200 of FIG. 7, the rotation control unit 710 obtains and detects the detection result of the internal pressure of the air turnbar 41 by the pressure sensor 45 (detection value (a) of the pressure sensor 45). The value (a) is converted into the tension (S). The conversion can be performed, for example, based on the detected value (a) -tension (S) conversion data stored in the RAM 73.

Next, in step S201, the rotation control unit 710 compares the tension (S) with a preset numerical value (tension set value (T)), and sets “tension (S) <tension set value (T)”. Determine if it exists. The tension set value (T) is stored in, for example, the RAM 73, and can be read out when the rotation control unit 710 is required.

If it is determined in step S201 that "tension (S) <tension set value (T)" (YES), the process proceeds to step S202, and the rotation control unit 710 increases the rotation speed of the drying drum 52 by Δv. Let me.

When it is determined in step S201 that "tension (S) ≥ tension set value (T)" (NO), the process proceeds to step S203, and the rotation control unit 710 reduces the rotation speed of the drying drum 52 by Δv. .. The processing from step S200 to step S203 is repeatedly executed, but the rotation control unit 710 can suspend or stop the processing at a necessary timing.

As shown in FIG. 7, the detected value of the internal pressure of the air turnstile 41 is converted into tension, compared with a preset value, and the rotation speed of the drying drum 52 (conveyance speed of the web-shaped recording medium 300) is adjusted. Then, tension control becomes possible. Therefore, the tension can be controlled by an inexpensive configuration in which the pressure detection mechanism such as the load cell arranged on the tension roller 51 is deleted.

The method shown in FIG. 7 is effective when handling a homogeneous web-shaped recording medium 300 because the internal pressure changes depending on the air permeability of the web-shaped recording medium 300 wound around the air turnstile 41.

Similarly, since the air turnstile 41 is a method of floating the web-shaped recording medium 300 by using air pressure, the floating amount changes depending on the air permeability of the material constituting the web-shaped recording medium 300. If the material has extremely high air permeability and the amount of levitation is too small, the undried ink image not only comes into contact with the outer peripheral surface 411 of the air turntile 41 and the image is distorted, but also the ink attached to the outer peripheral surface 411 follows. There is a risk of soiling the surface of the web-like recording medium 300. Further, if the material has a low air permeability, the floating amount becomes too large, and there is a risk of causing meandering due to fluttering. Therefore, it is desirable to control the floating amount of the web-shaped recording medium 300 within an appropriate range.

Here, a comparative example will be described. FIG. 8 is a diagram schematically showing an example of the image forming apparatus according to Comparative Example 1. As shown in FIG. 8, in the image forming apparatus 1X, a web-like recording medium 300 is bridged to a web support roller 17 composed of seven rollers, and an image forming unit 30 is arranged above the web support roller 17. ..

A length measuring roller 16 provided with an encoder 15 is arranged upstream of the image forming unit 30, and the ejection timing is corrected according to the conveyed amount of the web-shaped recording medium 300 based on the detection signal of the encoder 15 to correct the web. An image is formed on the state recording medium 300.

In FIG. 8, the positional relationship between the web-shaped recording medium 300 and the image forming unit 30 is maintained only by the tension of the web-shaped recording medium 300 on the web support roller 17. Therefore, it is inevitable that the web-shaped recording medium 300 will have a parallelism error between the rollers constituting the web support roller 17, and fluttering or meandering due to the influence of runout.

When fluttering occurs, the distance between the IJ head constituting the image forming unit 30 and the web-shaped recording medium 300 changes, so that an error in the landing position in the transport direction appears. When meandering occurs, a landing position error in the width direction appears. Further, when the web-shaped recording medium 300 comes into contact with the nozzle surface of the IJ head, missing print dots occur due to nozzle clogging. Therefore, the distance between the IJ head and the print medium is set in consideration of the fluttering of the web-shaped recording medium 300. It is necessary and causes deterioration of the landing position accuracy.

By setting the tension of the web-like recording medium 300 high, fluttering and meandering can be reduced, but since there is an adverse effect due to the tension being too high, if the conditions cannot be satisfied, there are restrictions on the use of the web-like recording medium 300. Occur. For example, when the tension is extremely high on paper media, the elastic modulus decreases due to ink penetration depending on the print coverage of the ink on the upstream side, the print media stretches, and the ink lands due to insufficient transport amount. Positional error occurs.

Further, in the case of OPP (Oriented Polypropylene) having a thickness of 20 μm of the flexible packaging media, if the tension exceeds 100 N / m, tension wrinkles occur and an landing position error occurs. As described above, although the method shown in FIG. 8 has a simple configuration, it has a drawback that the applicable recording media are limited.

FIG. 9 is a diagram schematically showing an example of the image forming apparatus according to Comparative Example 2. As shown in FIG. 9, the image forming apparatus 1Y has the platen drum 20 as in FIG. 1, but unlike FIG. 1, it does not have the air turnbar system 40.

In the image forming apparatus 1Y, the web-shaped recording medium 300 printed by the image forming unit 30 is wound around the platen drum 20 at a winding angle at which sufficient transport force can be obtained and conveyed, and is conveyed downward by the platen drum 20 downward. It is transported from 20 to the drying unit 50.

Since an undried ink image is formed on the image forming surface of the web-shaped recording medium 300 coming out of the platen drum 20, it is in contact with any transport member until the ink is dried and formed into a contactable state. Can not do it.

Here, the image forming portion 30 is arranged along the outer periphery of the platen drum 20, and the left end portion of the image forming portion 30 in the transport direction is below the horizontal tangent line passing through the uppermost portion of the outer periphery of the platen drum 20. positioned.

Therefore, the drying portion 50 is arranged on the left side of the platen drum 20 so as not to overlap with the platen drum 20 in a plan view, and the web-shaped recording medium 300 cannot be horizontally conveyed from the platen drum 20 toward the drying portion 50. .. This is because the image forming surface of the web-shaped recording medium 300 comes into contact with the left end portion of the image forming portion 30 in the transport direction.

Therefore, in FIG. 9, the drying portion 50 is arranged substantially below the platen drum 20 so that the image forming surface of the web-shaped recording medium 300 can be introduced into the drying portion 50 without touching anywhere.

By the way, in order to dry the ink in the drying unit 50, a heating temperature and a heating time according to the physical characteristics of the ink and the printing medium are required. In a high-speed image forming apparatus, in order to secure the heating time, it is necessary to provide a long heating and conveying distance according to the conveying speed, and the apparatus tends to be large in size.

Therefore, in the case of a configuration in which the drying portion 50 is arranged under the platen drum 20 as in the image forming apparatus 1Y, the height of the apparatus cannot be avoided, and a height exceeding 2 m may be required. When the device becomes taller, the operability of the web-shaped recording medium 300, such as loading work, deteriorates. Also, in the case of equipment transportation, the height of the transportation container is generally about 2.5 m, so if an equipment exceeding 2 m is packed, it is highly likely that the height will exceed 2.5 m, and the equipment was assembled. It may not be possible to transport in a state.

When transporting equipment that exceeds the allowable height of the shipping container, the equipment must be disassembled and transported, so the equipment installation after transportation must be assembled locally, which leads to the problem of prolonged equipment installation. ..

In the image forming apparatus 1Y, the web-shaped recording medium 300 can be pulled out to the right from the lowest point of the platen drum 20 as an arrangement for avoiding the heightening of the apparatus. However, in this case, since the drying section 50 is arranged on the right side of the platen drum 20, the length of the transport path of the paper feed transport section to the platen drum 20 and the extension of the transport path from the drying section 50 to the discharge port 102 are extended. Therefore, it causes a problem that the spoilage (waste paper, waste paper) at the time of starting and stopping printing increases.

On the other hand, in the image forming apparatus 1 shown in FIG. 1, an air turn bar 41 having a plurality of air ejection holes 412 provided on an outer peripheral surface 411 around which the web-shaped recording medium 300 is wound is provided downstream of the platen drum 20. An air turnbar system 40 having a blower 42 that sends air to the air turn bar 41 is arranged.

As a result, even if the image forming surface (printing surface) of the web-shaped recording medium 300 on which the image is formed by the image forming unit 30 faces the outer peripheral surface 411 of the air turn bar 41 and is conveyed, the image forming surface and the air turn bar 41 It is possible to maintain a non-contact state with. Therefore, the transport direction can be changed along the outer peripheral surface 411 of the air turn bar 41 without disturbing the image formed on the image forming surface.

As a result, the platen drum 20 and the drying portion 50 can be arranged at positions that do not overlap in a plan view, so that the transport path length can be shortened and the height and size of the device can be suppressed. can. Further, since the transport path length can be shortened, it is possible to realize an image forming apparatus without an increase in spoilage (waste paper, waste paper).

Further, in the image forming apparatus 1, a web-shaped recording medium 300 is wound around the platen drum 20, and an image forming unit 30 composed of, for example, IJ head arrays 31 to 35 is arranged around the platen drum 20. This makes it possible to reduce variations due to the characteristics of the web-shaped recording medium 300 and the influence of expansion and contraction vibration during transportation, and further, the distance between the IJ head arrays 31 to 35 and the web-shaped recording medium 300 can be set small.

As a result, the landing variation of the ink when forming an image on the web-shaped recording medium 300 is reduced, and the image quality formed on the web-shaped recording medium 300 can be improved. Further, since there are no restrictions on the type of the web-shaped recording medium 300 and complicated landing position adjustment for each web-shaped recording medium 300 is not required, the ink landing position accuracy can be stably maintained.

<Modified example of the first embodiment>
In the modified example of the first embodiment, an example using an air turnbar system having specifications different from those of the first embodiment is shown. In the modified example of the first embodiment, the description of the same component as that of the above-described embodiment may be omitted.

FIG. 10 is a schematic diagram illustrating a configuration example of an air turnstile system according to a modified example of the first embodiment. As shown in FIG. 10, the air turnstile system 40A arranges the displacement sensor 46 facing the back surface of the web-shaped recording medium 300 so as to sandwich the web-shaped recording medium 300 between the air turnbar system 40A and the outer peripheral surface 411. This is different from the air turn bar system 40 (see FIG. 5A).

The displacement sensor 46 is configured to be able to detect the floating amount of the web-shaped recording medium 300. As the displacement sensor 46, for example, an optical type or ultrasonic type non-contact displacement sensor can be used. The displacement sensor 46 is a typical example of the levitation amount detecting unit according to the present invention.

The floating amount of the web-shaped recording medium 300 by the air turn bar 41 is near the apex of the arc of the outer peripheral surface 411 having an arc-shaped region in the side view of the outer peripheral surface 411 of the air turn bar 41, or in the width direction of the web-shaped recording medium 300. It tends to be less than other parts near the end (direction orthogonal to the transport direction).

Therefore, the displacement sensors 46 may be singular or plural, but are arranged in one or both of the vicinity of the apex of the arc of the outer peripheral surface 411 of the air turnbar 41 and the vicinity of the end portion in the width direction of the web-shaped recording medium 300. Is preferable. This is because the floating amount of the web-shaped recording medium 300 is insufficient, and it is possible to reliably prevent the undried ink image from coming into contact with the outer peripheral surface 411 of the air turnstile 41.

In the air turn bar system 40A, the gas supply amount control unit 740 of the control unit 70 compares the floating amount of the web-shaped recording medium 300 detected by the displacement sensor 46 with a preset numerical value, and the blower 42 supplies the gas based on the comparison result. It is possible to control the amount of gas supplied.

Specifically, as shown in step S300 of FIG. 11, the gas supply amount control unit 740 of the control unit 70 obtains the detection result of the displacement sensor 46 (detection value (d) of the floating amount of the web-shaped recording medium 300). Obtain.

Next, in step S301, the gas supply amount control unit 740 compares the detected value (d) of the displacement sensor 46 with the preset numerical value (displacement amount set value (e)), and “detects the displacement sensor 46”. It is determined whether or not the value (d) <displacement amount set value (e) ”. The displacement amount set value (e) is stored in the RAM 73, for example, and can be read out when the gas supply amount control unit 740 is required.

If it is determined in step S301 that "displacement sensor 46 detection value (d) <displacement amount setting value (e)" (YES), the process proceeds to step S302, and the gas supply amount control unit 740 moves to the blower. The supply amount of the gas supplied by 42 is increased by Δp.

If it is determined in step S301 that "displacement sensor 46 detection value (d) ≥ displacement amount setting value (e)" (NO), the process proceeds to step S303, and the gas supply amount control unit 740 moves to the blower. The supply amount of the gas supplied by 42 is reduced by Δp. The process from step S300 to step S303 is repeatedly executed, but the gas supply amount control unit 740 can suspend or stop the process at a necessary timing.

By performing the control shown in FIG. 11, it becomes possible to control the floating amount of the web-shaped recording medium 300 within an appropriate range.

On the other hand, the floating amount of the web-shaped recording medium 300 also changes depending on the tension of the web-shaped recording medium 300. For example, when the tension of the web-shaped recording medium 300 is large, the levitation amount decreases, and when the tension is small, the levitation amount increases.

Therefore, in addition to controlling the output of the blower 42 by the control unit 70, by controlling the rotation speed of the drying drum 52 so that the tension detected by the tension roller 51 is within an appropriate range, air can be used in a wider variety of media. The amount of levitation at the turn bar 41 can be controlled.

Specifically, in step S400 of FIG. 12, the gas supply amount control unit 740 of the control unit 70 sets the variable i to i = 1. Next, in step S401, the gas supply amount control unit 740 sets the variable j to j = 1. Next, in step S402, the gas supply amount control unit 740 compares i and N and determines whether or not “i ≦ N”. Here, N is the number of retries.

If it is determined in step S402 that "i ≦ N" (YES), the process proceeds to step S403, and the gas supply amount control unit 740 compares j and M, and is “j ≦ M”. Judge whether or not. Here, M is the number of retries.

If it is determined in step S403 that "j≤M" (YES), the process proceeds to step S404, and the gas supply amount control unit 740 of the control unit 70 detects the detection result (web-like recording medium) of the displacement sensor 46. The detected value (d) of the levitation amount of 300 is obtained.

Next, in step S405, the gas supply amount control unit 740 compares the detected value (d) of the displacement sensor 46 with the preset numerical value (displacement amount set value (e)), and “detects the displacement sensor 46”. It is determined whether or not the value (d) <displacement amount set value (e) ”. The displacement amount set value (e) is stored in the RAM 73, for example, and can be read out when the gas supply amount control unit 740 is required.

If it is determined in step S405 that "displacement sensor 46 detection value (d) <displacement amount setting value (e)" (YES), the process proceeds to step S406, and the gas supply amount control unit 740 moves to the blower. The supply amount of the gas supplied by 42 is increased by Δp. Then, in step S407, the gas supply amount control unit 740 sets i = i + 1, shifts to step S402, and repeats the same processing thereafter.

If it is determined in step S405 that "displacement sensor 46 detection value (d) ≥ displacement amount setting value (e)" (NO), the process proceeds to step S408, and the gas supply amount control unit 740 moves to the blower. The supply amount of the gas supplied by 42 is reduced by Δp. Then, in step S409, the gas supply amount control unit 740 sets j = j + 1, shifts to step S403, and repeats the same processing thereafter.

On the other hand, when it is determined in step S402 that "i> N" (NO), the process proceeds to step S410, and the rotation control unit 710 of the control unit 70 sets the tension set value (T) to T-α. Lower. Here, α is an appropriately set amount of change in tension.

Next, in step S411, the rotation control unit 710 obtains the tension (S) detected by the tension roller 51. Next, in step S412, the rotation control unit 710 compares the tension (S) with the tension set value (T) changed in step S410, and in "tension (S) <tension set value (T)". Determine if it exists.

If it is determined in step S412 that "tension (S) <tension set value (T)" (YES), the process proceeds to step S400, and the same process is repeated thereafter.

When it is determined in step S412 that "tension (S) ≥ tension set value (T)" (NO), the process proceeds to step S413, and the rotation control unit 710 reduces the rotation speed of the drying drum 52 by Δv. .. After that, the process proceeds to step S411, and the same processing is repeated thereafter.

If it is determined in step S403 that "j> M" (NO), the process proceeds to step S420, and the rotation control unit 710 of the control unit 70 raises the tension set value (T) to T + α.

Next, in step S421, the rotation control unit 710 obtains the tension (S) detected by the tension roller 51. Next, in step S422, the rotation control unit 710 compares the tension (S) with the tension set value (T) changed in step S420, and “tension (S) ≧ tension set value (T)”. Determine if it exists.

If it is determined in step S422 that "tension (S) ≥ tension set value (T)" (YES), the process proceeds to step S400, and the same process is repeated thereafter.

When it is determined in step S422 that "tension (S) <tension set value (T)" (in the case of NO), the process proceeds to step S423, and the rotation control unit 710 increases the rotation speed of the drying drum 52 by Δv. .. After that, the process proceeds to step S421, and the same processing is repeated thereafter.

By performing the control shown in FIG. 12, it becomes possible to control the amount of floating in the air turnstile with a wider variety of media, and it becomes possible to provide an image forming apparatus having high media compatibility.

Although the preferred embodiment has been described in detail above, it is not limited to the above-described embodiment, and various modifications and substitutions are made to the above-mentioned embodiment without departing from the scope of the claims. Can be added.

For example, in the above embodiment, the image forming apparatus provided with the conveying device according to the present invention has been described, but the conveying device according to the present invention can be widely applied to an apparatus for discharging a liquid including an image forming apparatus. can.

Here, the "device for discharging a liquid" is a device provided with a liquid discharge head or a liquid discharge unit which is a liquid discharge unit, and drives the liquid discharge unit to discharge the liquid. The device for discharging a liquid includes not only a device capable of discharging a liquid to a device to which the liquid can adhere, but also a device for discharging the liquid into the air or into the liquid.

The "device for discharging the liquid" can also include means for feeding, transporting, and discharging paper to which the liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "device that ejects a liquid", in addition to an image forming apparatus that is a device that ejects ink to form an image on paper, powder is used to form a three-dimensional object (three-dimensional object). Examples thereof include a three-dimensional modeling device (three-dimensional modeling device) that discharges a modeling liquid into a powder layer formed in layers.

Further, the "device for discharging a liquid" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "material to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as one that adheres and adheres, and one that adheres and permeates. Specific examples include paper, recording paper, recording paper, film, recorded media such as cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and media such as inspection cells. Yes, and unless otherwise specified, it includes everything to which the liquid adheres.

The material of the above-mentioned "material to which liquid can adhere" may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics or the like as long as the liquid can adhere even temporarily.

Further, the "liquid" includes an ink, a treatment liquid, a DNA sample, a resist, a pattern material, a binder, a modeling liquid, or a solution containing amino acids, proteins and calcium, and a dispersion liquid.

Further, the "device for discharging the liquid" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as a "device for ejecting liquid", a treatment liquid coating device for ejecting a treatment liquid to the paper for the purpose of modifying the surface of the paper, and a raw material. There is an injection granulator which granulates fine particles of raw materials by injecting a composition liquid in which the above-mentioned material is dispersed in a solution through a nozzle.

The "liquid discharge unit" is a liquid discharge head such as an IJ head integrated with functional parts and a mechanism, and is a collection of parts related to liquid discharge. For example, the "liquid discharge unit" includes a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, a main scanning movement mechanism in which at least one of the configurations is combined with a liquid discharge head, and the like.

Here, the term "integration" means, for example, a liquid discharge head and a functional component, a mechanism in which the mechanism is fixed to each other by fastening, bonding, engagement, etc., or one in which one is movably held with respect to the other. include. Further, the liquid discharge head, the functional parts, and the mechanism may be configured to be detachable from each other.

Further, the pressure generating means used for the "liquid discharge head" is not limited. For example, a piezoelectric actuator (which may use a laminated piezoelectric element), a thermal actuator using an electric heat conversion element such as a heat generating resistor, an electrostatic actuator composed of a diaphragm and a counter electrode, and the like can be used.

Further, in the terms of the present application, image formation, recording, printing, printing, printing, modeling, etc. are all synonymous.

1 Image forming device 10 Paper feed transfer unit 11, 49, 61 Transfer idler roller 12, 63 Transfer drive roller pair 12a, 63a Drive roller 12b, 63b Pinch roller 13 EPC device 14, 51, 62 Tension roller 20 Platen drum 25 Detection device 30 Image forming part 31, 32, 33, 34, 35 IJ head array 40, 40A Air turn bar system 41 Air turn bar 42 Blower 43 Filter 44 Gas flow path 45 Pressure sensor 46 Displacement sensor 50 Drying part 52 Drying drum 53 Heater 54 Air nozzle 60 Paper discharge transport unit 70 Control unit 71 CPU
72 ROM
73 RAM
74 I / F
75 Bus line 101 Inlet 102 Outlet 300 Web-like recording medium 411 Outer peripheral surface of air turntile 412 Air ejection hole 710 Rotation control unit 720 Discharge control unit 730 Drying control unit 740 Gas supply amount control unit

Japanese Unexamined Patent Publication No. 2013-169767

Claims (8)

A rotating body that winds the web-shaped recording medium around a predetermined area on the outer peripheral surface with one surface of the web-shaped recording medium facing outward, and conveys the web-shaped recording medium as it rotates.
A drying unit arranged downstream of the rotating body in the transport direction of the web-shaped recording medium to dry the web-shaped recording medium and transport the web-shaped recording medium.
It has a transport direction changing section which is arranged on the transport path of the web-shaped recording medium between the rotating body and the drying section and changes the transport direction of the web-shaped recording medium.
The outer peripheral surface of the transport direction changing portion includes a facing region facing the one surface of the web-shaped recording medium.
The facing region is provided with an opening for ejecting gas toward the one surface of the web-shaped recording medium.
The rotating body and the dried portion do not overlap in a plan view, and the dried portion is arranged closer to the discharge port of the web-shaped recording medium than the rotating body in a plan view.
The drying portion has a second rotating body that winds the web-shaped recording medium around a predetermined area on the outer peripheral surface and conveys the web-shaped recording medium as it rotates.
It has a pressure detecting unit that detects the internal pressure of the transport direction changing unit and a rotation control unit that controls the rotation speed of the second rotating body.
The rotation control unit detects the tension of the web-shaped recording medium based on the internal pressure detected by the pressure detection unit, compares the tension with a preset numerical value, and based on the comparison result, the second A transport device that controls the rotation speed of the rotating body ,
An image forming apparatus having an image forming portion arranged to face the outer peripheral surface of the rotating body and forming an image on one surface of the web-shaped recording medium . A rotating body that winds the web-shaped recording medium around a predetermined area on the outer peripheral surface with one surface of the web-shaped recording medium facing outward, and conveys the web-shaped recording medium as it rotates.
A drying unit arranged downstream of the rotating body in the transport direction of the web-shaped recording medium to dry the web-shaped recording medium and transport the web-shaped recording medium.
It has a transport direction changing section which is arranged on the transport path of the web-shaped recording medium between the rotating body and the drying section and changes the transport direction of the web-shaped recording medium.
The outer peripheral surface of the transport direction changing portion includes a facing region facing the one surface of the web-shaped recording medium.
The facing region is provided with an opening for ejecting gas toward the one surface of the web-shaped recording medium.
The rotating body and the dried portion do not overlap in a plan view, and the dried portion is arranged closer to the discharge port of the web-shaped recording medium than the rotating body in a plan view.
The drying portion has a second rotating body that winds the web-shaped recording medium around a predetermined area on the outer peripheral surface and conveys the web-shaped recording medium as it rotates.
It has a pressure detecting unit that detects the internal pressure of the transport direction changing unit and a rotation control unit that controls the rotation speed of the second rotating body.
The rotation control unit detects the tension of the web-shaped recording medium based on the internal pressure detected by the pressure detection unit, compares the tension with a preset numerical value, and based on the comparison result, the second A transport device that controls the rotation speed of the rotating body ,
A device for ejecting a liquid having a liquid ejection portion arranged to face the outer peripheral surface of the rotating body and ejecting the liquid to one surface of the web-shaped recording medium . A rotating body that winds the web-shaped recording medium around a predetermined area on the outer peripheral surface with one surface of the web-shaped recording medium facing outward, and conveys the web-shaped recording medium as it rotates.
A drying unit arranged downstream of the rotating body in the transport direction of the web-shaped recording medium to dry the web-shaped recording medium and transport the web-shaped recording medium.
It has a transport direction changing section which is arranged on the transport path of the web-shaped recording medium between the rotating body and the drying section and changes the transport direction of the web-shaped recording medium.
The outer peripheral surface of the transport direction changing portion includes a facing region facing the one surface of the web-shaped recording medium.
The facing region is provided with an opening for ejecting gas toward the one surface of the web-shaped recording medium.
The rotating body and the dried portion do not overlap in a plan view, and the dried portion is arranged closer to the discharge port of the web-shaped recording medium than the rotating body in a plan view.
A pressure detecting unit that detects the internal pressure of the transport direction changing unit, a gas supply unit that supplies the gas to the transport direction changing unit, and a gas supply amount that controls the supply amount of the gas supplied by the gas supply unit. With a control unit,
The gas supply amount control unit is a transfer device that compares the internal pressure detected by the pressure detection unit with a preset numerical value and controls the supply amount of the gas supplied by the gas supply unit based on the comparison result. ,
An image forming apparatus having an image forming portion arranged to face the outer peripheral surface of the rotating body and forming an image on one surface of the web-shaped recording medium . A rotating body that winds the web-shaped recording medium around a predetermined area on the outer peripheral surface with one surface of the web-shaped recording medium facing outward, and conveys the web-shaped recording medium as it rotates.
A drying unit arranged downstream of the rotating body in the transport direction of the web-shaped recording medium to dry the web-shaped recording medium and transport the web-shaped recording medium.
It has a transport direction changing section which is arranged on the transport path of the web-shaped recording medium between the rotating body and the drying section and changes the transport direction of the web-shaped recording medium.
The outer peripheral surface of the transport direction changing portion includes a facing region facing the one surface of the web-shaped recording medium.
The facing region is provided with an opening for ejecting gas toward the one surface of the web-shaped recording medium.
The rotating body and the dried portion do not overlap in a plan view, and the dried portion is arranged closer to the discharge port of the web-shaped recording medium than the rotating body in a plan view.
A pressure detecting unit that detects the internal pressure of the transport direction changing unit, a gas supply unit that supplies the gas to the transport direction changing unit, and a gas supply amount that controls the supply amount of the gas supplied by the gas supply unit. With a control unit,
The gas supply amount control unit is a transfer device that compares the internal pressure detected by the pressure detection unit with a preset numerical value and controls the supply amount of the gas supplied by the gas supply unit based on the comparison result. ,
A device for ejecting a liquid having a liquid ejection portion arranged to face the outer peripheral surface of the rotating body and ejecting the liquid to one surface of the web-shaped recording medium . The transport device is
1 . The image forming apparatus according to. The transport device is
2 . A device for discharging the liquid described in 1. The image forming apparatus according to claim 1 , 3, or 5 , wherein the image is formed of water-based ink, and the drying portion dries the water-based ink. The image forming apparatus according to claim 1 , 3, 5, or 7 , wherein the image forming unit includes a plurality of inkjet recording heads juxtaposed in a direction orthogonal to the transport direction of the web-shaped recording medium.

Images